When the ignition switch is placed to the ON position, the ESC indicator light illuminates, then goes off if the ESC system is operating normally.
The ESC indicator light blinks whenever the ESC is operating.
If ESC indicator light stays on, your vehicle may have a malfunction with the ESC system. When this warning light illuminates have your vehicle checked by an authorized HYUNDAI dealer as soon as possible.
The ESC OFF indicator light comes on when the ESC is turned off.
WARNING
When the ESC is blinking, this indicates the ESC is active:
Drive slowly and NEVER attempt to accelerate. NEVER turn the ESC off while the ESC indicator light is blinking or you may lose control of the vehicle resulting in an accident.
NOTICE
Driving with varying tire or wheel sizes may cause the ESC system to malfunction. When replacing tires, make sure they are the same size as your original tires for this vehicle.
Hyundai Sonata LF 2014-2019 Service Manual: Troubleshooting
Troubleshooting
Trouble SymptomProbable CauseRemedyExcessive play in steeringLoose U-joint boltRetighten or replace as necessaryLoose yoke plugRetightenLoose steering gear mounting boltsRetightenLoose or worn tie rod endRetighten or replace as necessarySteering wheel does not return properlyExc ...
Hyundai Sonata LF 2014-2019 Owners Manual: Smart key precautions
The smart key will not work if any of the following occur:
The smart key is close to a radio transmitter such as a radio station or
an airport which can interfere with normal operation of the transmitter.
The smart key is near a mobile two way radio system or a cellular phone.
Another vehicleâ ...